Production build

Following instructions from official React documentation, suppose
your package main attribute points to your entry file, for instance index.js,
and your bundle file is dist/NAME.min.js, where NAME is
your package name, you could add an npm script like the following

Customization

src folder

You may want to organize your code into a src/ folder, if so, do

mkdir src
mv index.js src/

Then edit your package.json

"main":"src/index.js"

For sure it is also a good idea to create a src/components/ folder and a Root.js implementing your <Root /> component.
By the way, I like to start almost from scratch with the structure I feel more inspiring for that project.
For example; if hosted on Heroku I create a public/ folder; if hosted on AWS I like more a bucket/ or (in some cases) buckets/ folder.
Programming is a creative process, you know.

Babel preset env

You may want to customize it, for more details see [babel-preset-env].

Browserslist

Default .browserslist created on postinstall is the following.

> 0.5%
last 2 versions
Firefox ESR
not dead

You may want to edit target browsers, for more details see browserslist.

Async Redux

Probably you need to call an asynchronous API: the standard way is to use
the Redux Thunk middleware, so you need to install

npm install redux-thunk --save

This choice is up to you. For example you could prefer redux-saga.
Since there are few alternatives this package does not include a middleware to dispatch async actions.
See Async Actions chapter on official Redux documentation for details.
In my opinion redux-thunk is a really good choice: it is stable, battle tested, has a very good documentation and a flat learning curve.

Linter

It is strongly recommended to lint your code. Do not think it too much, just launch

npm i pre-commit standard -D

and add the following to your package.json

"scripts":{"lint":"standard"},"pre-commit":["lint"]

Now on every commit, you will check the code with standard linter. If you like semicolons you can go for semistandard.